Method and system for producing oil tenaciously held in porous formations using a dredging operation



April 7, 1959 E. v. BERGSTROM 2,880,981

METHOD AND SYSTEM FOR PRODUCFNG OIL TENACIOUSLY HELD IN ,Filed Jan. 30, 1958 POROUS FORMATIONS USING A DREDGING OPERATION r m mzorrom o $5. an. t2: iuzfiimms r A Unite-d tates. O

METHOD AND SYSTEM FOR PRODUCING OIL TENACIOUSLY HELD IN POROUS FORMATIONS USING A DREDGING OPERATION Eric V. Bergslrom, Byram, Conn., assignor to Socony Mobil Oil Company, Inc., a corporation of New York Application January 30, 1958 Serial No. 112,209 15 Claims. 01. 262-2) This invention relates to a method and system for producing oil, more particularly to a method and system for producing oil from formations in which it is tenaciously held to the extent that it will not flow of its own volition into wells which penetrate these formations.

Throughout the United States, Canada and possibly in other countries, there exist vast deposits of oil in Athabasca tar sands and other formations. This oil, which may be of high viscosity, is tenaciously .held in these formations to the extent that, although a well is drilled into the formations, the oil will not flow of its own volition into the well so that it can beproduced. Heretofore, such oil has been produced by strip mining methods, followed by the separation of the oil from the sand. This method of producing such oil has met with some success, but, necessitates the handling of the sandoil mixture at least twice; once by mining the oil-con-- taining formation and again when it is conveyed to a separation center where the oil is separated from the: formation particles.

The present invention provides a method and system; for producing oil from a tar sand which necessitates thehandling of the tar sand only once. This is effected by a dredging operation in which hot water is entrained with. the dredged oil-containing sand. In passing through the dredge, the sand particles and hot water commingle and. F

in so doing the hot water releases the tar oil from the,

sand particles. At the dredge discharge the sand, oil and water will separate; the sand will settleto the bottom;

of the pond, the water will mix with the other water in. the pond, while the oil will rise to the surface and float on. the water. The. oil can then be removed by a skimming" pump and conveyed to storage and processing facilities- Where the viscosity of the recovered oil permits, the oil can be introduced directly from the storage facilities into a transportation pipe line. In many instances, however,

the viscosity. of the oil is too high and must be cut by a. light oil. The light oil is obtained by feeding the heavy oil into a coker or a fractionator. The light oils so formed may then be used as a cutting oil to reduce the viscosity of the oil from storage so that it will be suitable for pipe: line. The heavy fractions or bottoms are conveyed to' the boiler plant where they are used as fuel in the gen-- eration of steam for continuing the recovery operation..

When the released oil has a high density, equal to or greater than that of water, .alow density cutting oil is: introduced into the stream of hot water and tar sand particles passing through the dredge to mix with released. tar sand oil and produce an oil at the discharge end of" the dredge that is light enough to float on the surface: of the water. A cutting oil for this purpose may be light. products from the fractionating facilities. The cuttingoil is piped to the barge andv introduced into the dredge. stream at some point between. the suction anddischarge.

ends thereof.

The tar sand, which has been removed from the forma-- tion inv the vicinity of the front of the barge, is conveyed.v

by the dredge to a remote point in the pond, preferably 2,880,981 Patented Apr. 7,;1959

in back of the barge, where the sand, which has had the oil released therefrom by commingling in transit through the dredge system with hot water and/or hot water and cutting oil, is deposited. By advancing the barge on the pond as the dredging operation proceeds, the pond, in effect, is advanced with the barge.

Therefore, the primary object of this invention is to provide a method and system for producing oil from a formation such as an Athabasca. tar sand. Another object. of the invention is to provide a method for producing oil from a tarsand by a dredging operation. Still another object of this invention is to provide a pond of water which has been heated to a temperature that may be as high as F. that will release the oil held by the sand as a dredging operation is being conducted, This invention also contemplates reducing the density of the released oil when its density is equal to or greater than that of Water. It is also an object of this invention to provide a heat insulating cover for the surface of the pond for the purpose of reducing heat loss to the atmosphere. Other objects and advantages of the present invention will become apparent from the following detailed description when considered with the drawing in which the single figure is a schematic view which is in part a flow diagram and in part a vertical sectional view of the earths surface showing the manner in which oil is recovered by a dredging operation.

Referring to the drawing in detail, a pond 10, which has been formed in an Athabasca tar sand 11, has floating thereon a barge 12. Mounted on the barge 12 is a conventional dredging machine having a suction nozzle 13, a dredge pump 14, and a discharge pipe 15. Barge 12 is held in position horizontally by cables 16, which extend from remotely located winches 17 to the barge 12. Open steam from a boiler plant 18 is introduced into the pond 10 by means of the pipe line 19 which terminates below the surface of the water in the pond. Steam introduced by pipe 19 heats the water in the pond to a temperature that may be as high as 190 F. Heat radiation from the pond to the atmosphere may be reduced by covering the surface of the pond with a granular heat insulating material such as micro-spherical balloons, granulated cork or with plastic foam slabs made from a plastic that will not be attacked by. the oil. This insulating covering also serves the purpose of reducing fire hazards.

Portions of the oil-containing formation, along wtih hot water, are removed from the bottom and side walls of the pond by suction created at the inlet nozzle 13 by the dredge pump 14 and conveyed by the dredge outlet line 15 to a remote area of the pond where it is discharged. Sand freed of oil is deposited, as for example,

at point 20; the water discharged from the pipe 15 mingles with the water in the pond 10; and the oil will float on the surface of the pond. The oil is removed from the surface of the pond by a skimming pump 21 having a suction nozzle 22 and a discharge pipe 23. Discharge pipe 23 leads to storage facilities represented in the draw ings by tank 24. The oil can then be pumped from the storage facilities by pump 25 directly into the'pipe line 26 for transportation, or, in the case of high viscosity, be introduced into a viscosity-breaking unit represented in the drawings by a coker 27 and a fractionating unit 28. From the viscosity-breaking unit, the lighter fractions can be introduced, by pump 29 and pipe 30, directly into the transportation pipe line 26, while the bottom or heavier fractions can be removed from the fractionating' water, it will not float upon the surface of the pond where it can be removed by the skimming pump. 21. Under these conditions, a portion of the light products from the fractionating unit 28 is conducted by pipe 33 to the dredge pump 14 where it is entrained with the tar sand and hot water passing therethrough. The introduction of this cutting oil into the dredge stream will mix it with the high density oil being separated from the sand, and, in so doing, will reduce the density of the oil dis.- charged through the pipe 15 to the extent that it will float upon the surface of the pond and can be removed by the skimming pump.

As the oil-containing sand is removed from the bottom, end and side walls of the pond in the vicinity of the front of the barge, clean sand is deposited by the dredge discharge at the remote point 20 in the pond that is preferably in back of the barge. The dredging operation conducted in this manner in effect moves the pond forward as the dredging operation progresses.

Since this operation is conducted on a pond of elevated temperature, the dredging machinery located in the barge house 34 is preferably operated from a remote point. This, however, is not necessary for the house 34 can be air conditioned so that the operator can occupy the house 34 and manually operate the machinery contained therein.

I claim:

1. A method of producing oil of high viscosity from a formation in which it is held tenaciously that comprises the steps of forming an excavation in the formation, filling the excavation with water to form a pond, heating the water to a temperature that is high enough to free oil from the formation particles, removing portions of the oil-containing formation by dredge and depositing said portions and entrained hot water in another area of the pond, and recovering the oil released by said hot water from the surface of the pond.

2. A method of producing oil of high viscosity from a formation in which it is held tenaciously that comprises the steps of excavating enough of the formation to form a pond, filling the pond with water, heating the Water to a temperature that is approximately 190 F. to free the oil from the formation particles contacted by the water, continuously removing the oil-containing particles from the sides and bottom of the pond and depositing them along with entrained water in another area of the pond, and recovering the oil released from the particles by the entrained hot water from the surface of the pond.

3. A method of producing oil of high viscosity from a tar sand in which it is held tenaciously that comprises the steps of forming an excavation in the tar sand, filling the excavation with water to form a pond, heating the water to a temperature that is high enough to free oil from the sand by introducing open steam into the pond below the surface of the water, removing the tar sand and entrained hot water by dredge and depositing it in another area of the pond, and recovering the oil released from the sand particles by the hot water from the surface of the pond.

4. A method of producing oil of high viscosity from a tar sand in which it is held tenaciously that comprises the steps of forming an excavation in the tar sand, filling the excavationwith water to form a pond, heating the water to a temperature that is high enough to free oil from the sand by introducing open, steam into the pond below the surface of the water, removing the tar sand and entrained hot water by dredge and depositing it in another area of the pond, pumping the oil released from the sand particlesv by the hot water from the surface of the pond, and conducting it to storage. and processing facilities.

;5. A method of producing oil of high viscosity from a formation in which it is held tenaciously to the extent that it will not flow into a well which penetrates the formation that comprises the steps of forming an excavation in the surface of the formation, filling the excavation with water to form a pond, heating the water to a temperature that is high enough to free oil from the formation particles by introducing open steam into the water, removing the oil-containing formation particles and entrained hot water by dredge and depositing it in another area of the pond, advancing the barge on the pond as the oil-free sand is removed and recovering the oil from the surface of the pond.

6. A method of producingoil of high viscosity and high density from a formation in which it is tenaciously held that comprises the steps of forming an excavation in the surface of the formation, filling the excavation with water to, form a pond, heating the water by introducing open steam thereinto to a temperature that is high enough to free oil from the formation particles, removing portions of the oil-containing formation by dredge and depositing said portions and entrained hot water in another: areaof thetpond, introducing a cutting oil into the dredge-entrained portions of the formation and hot water. to reduce. the density of the oil released from the dredge formation,.and. recovering the released cut oil of. lower density from the surface of the pond.

7. A system for producing an oil of high viscosity from a tar sand that comprises means defining a water filled pond in the tar sand, means. for heating the water in said pond to free'oilfrom the. sand contacted by the heated water, commonv means for removing. the oilcontaining tar sand from the sides and bottom of the pond and for intimately contacting it with the hot water, means for. depositing the oil, sand and hot water in an-. other area ofthe pond, and means for removing oil released from the sand by the hot water.

8. A system for producing an oil of high viscosity from a tar. sand that comprises means defining. a water filled pond in the tar sand, means for heating the water in said pond to free oil from the sand contacted by the heated water, a barge floating on the pond, common means carried by said barge for removing the oil-containing tar sand from the sides and bottom of the pond and for intimately contacting it with the hot water, means for depositing the oil, sand and hot water in another area of the pond, and means for removing oil released fromv the sand by the hot water.

9. A system for producing an oil of high viscosity from a tar sand that comprises means defining a water filled pond in the tar sand, means for heating the water in said pond to free oil from the sand contacted by the heated water, a barge; floating on the'pond, common means carried by said barge for removing the oil-containing tar sand from the sides and bottom of the pond and for intimately contacting it with the hot water, meansfor depositing. the oil, sand and hot water in an-.. other area of the pond, anda pump also carried by said barge for removing oil released from the sand by the hot water.

10. A system for producing an. oil of high viscosity from a tar sand that comprises means defining a water filled pond in the tar sand, means for heating the water in said pond to free oil from the sand contacted by the heated .water, a bargefloating on said pond, a remotely operated .dredgecarried by said barge for removing the oilacontaining tar. sandzfrorn the sides and bottom of the pond and for intimately contacting it! with the. hot Water, means for depositing'the oil, sand and hot water in another area of the pond, and a pump also carried by said barge for removing oil released from the sand by the hot water.

11. A system for-producing. an. oil of .high viscosity from a tar sand that comprises means defining a water filled pond in the. tar 'sand,.m eans, for heating the water in. said pond to free oil. from the sand. contacted by the:

heated water, a barge floating on said pond, a remotely operated dredgecarried by said'barge for removing the oil-containingwtar sand from the sides, and bottom of the pond and for intimately contacting it with the hot water, means for depositing the oil, sand and hot water in another area of the pond, a pump also carried by said barge for removing oil released from the sand by the hot water, and means for moving the barge along the surface of the pond as the oil-containing tar sand is dredged from the bottom and walls of the pond.

12. A system for producing an oil of high viscosity from a tar sand that comprises means defining a water filled pond in the tar sand, means for heating the water in said pond to free oil from the sand contacted by the heated water, heat insulating means covering the surface of the pond, a barge floating on said pond, a remotely operated dredge carried by said barge for removing the oil-containing tar sand from the sides and bottom of the pond and for intimately contacting it with the hot water, means for depositing the oil, sand and hot water in another area of the pond, and a pump also carried by said barge for removing oil released from the sand by the hot water.

13. A system for producing an oil of high viscosity from a tar sand that comprises means defining a water filled pond in the tar sand, means for heating the water in said pond to free oil from the sand contacted by the heated water, a barge floating on said pond, a dredge carried by said barge for removing the oil-containing tar sand from the sides and bottom of the pond and for intimately contacting it with the hot water, air conditioned quarters on said barge from which an operator can control the operation of the dredge, means for depositing the oil, sand and hot water in another area of the pond, and a pump also carried by said barge for removing oil released from the sand by the hot water.

14. A system for producing an oil of high viscosity and high density from a tar sand that comprises means defining a water filled pond in the tar sand, means for heating the water in said pond to free oil from the sand con tacted by the heated water, a barge floating on said pond, a dredge carried by said barge for removing the oil-containing tar sand from the sides and bottom of the pond for intimately contacting it with the hot water, said dredge including suction and exhaust means for picking up the oil-containing tar sand and for depositing the oil, sand and hot water in another area of the pond, means for introducing a cutting oil into the dredge between the suction and exhaust means to lower the density of the released oil so that it will float on the surface of the water in the pond, and a pump also carried by said barge for removing the floating oil.

15. A system for producing an oil of high viscosity and high density from a tar sand that comprises means defining a water filled pond in the tar sand, means for heating the water in said pond to tree oil from the sand contacted by the heated water, a barge floating on said pond, a dredge carried thereby provided with a pump, suction nozzle and exhaust conveyor means for removing the oil-containing tar sand from the sides and bottom of the pond and for intimately contacting it with the hot Water, means for depositing the oil, sand and hot water in another area of the pond, means for introducing a cutting oil into the dredge pump for entrainment with the hot water and oil-containing tar sand for reducing the density of the oil released from the tar sand, and a pump also carried by said barge for removing oil released from the sand by the hot water.

Schneiders May 30, 1922 Moss et a1 June 28, 1932 

1. A METHOD OF PRODUCING OIL OF HIGH VISCOSITY FROM A FORMATION IN WHICH IT IS HELD TENACIOUSLY THAT COMPRISES THE STEPS OF FORMING AN EXCAVATION IN THE FORMATION, FILLING THE EXCAVATION WITH WATER TO FORM A POND, HEATING THE WATER TO A TEMPERATURE THAT IS HIGH ENOUGH TO FREE OIL FROM THE FORMATION PARTICLES, REMOVING PORTIONS OF 